Ed, if you are referring to the measure enclosed by a box, I did the same thing. Just keep at it until you can play to your satisfaction (I resisted the urge to play the piece start to finish while I was doing this). I then added the second measure and played (with boxed part) over & over so I wouldn't "forget" what I'd just learned.

Ed, when you are practicing the piece try first learning to play the first voice until you can play it to your satisfaction, end to end.
Put another way, you would basically be skipping the notes played with your thumb (which is the second voice or line of the piece ).
I have tried this and it really helped. Let me know if this doesn't make sense and I'll record/upload an example of what I'm talking about.

Ed, when you are practicing the piece try first learning to play the first voice until you can play it to your satisfaction, end to end.
Put another way, you would basically be skipping the notes played with your thumb (which is the second voice or line of the piece ).
I have tried this and it really helped. Let me know if this doesn't make sense and I'll record/upload an example of what I'm talking about.

This is an interesting advice, Tom. I think I will try it me too. Thank you, Lucian